recently I added a new alias to my keystore to sign my app.
Now I lost the new generated file with the alias, but remember the password and the alias name and have an older copy the file. Is there a way to recreate the alias using this things?
You can list the contents of your keystore with the command:
keytool -list -keystore <name of keystore file>
To do this, you will need to provide the keystore password (not the alias password). This will tell you the aliases in the file, which are self-contained, allowing you to sign. If you wish, you could also extract keys using other options / tools.